Medical dressings, systems, and methods with thermally-enhanced vapor transmissions

ABSTRACT

Wounds dressings, systems, and methods are presented that involve using a patient&#39;s body heat to enhance liquid removal from the wound dressing through a high-moisture-vapor-transmission-rate drape. Additional heat sources or devices, such as nano-antennas or electrical heating elements, may be added or used separately to enhance the removal liquid from the wound dressing. Other dressings, systems, and methods are presented herein.

RELATED APPLICATIONS

The present invention claims the benefit, under 35 USC §119(e), of thefiling of U.S. Provisional Patent Application Ser. No. 61/560,090,entitled “Medical Dressing, Systems, and Methods with Thermally EnhancedVapor Transmission,” by Pratt et al., filed Nov. 15, 2011, which isincorporated herein by reference for all purposes.

FIELD

The present disclosure relates generally to medical treatment systemsfor treating wounds that produce liquids, such as exudate, and moreparticularly, but not by way of limitation, to medical dressings,systems, and methods with thermally-enhanced vapor transmission.

BACKGROUND

Caring for wounds is important in the healing process. Wounds oftenproduce considerable liquids, e.g., exudate. Medical dressings are oftenused in wound care to address the production of liquids from the wound.If not properly addressed, liquids at the wound can lead to infection ormaceration of the periwound area As used throughout this document, “or”does not require mutual exclusivity. Wound dressings may be used aloneor as an aspect of applying reduced pressure to a tissue site.

SUMMARY

According to an illustrative embodiment, a wound dressing includes ahigh-moisture-vapor-transmission-rate drape having a first side and asecond, patient-facing side and includes a thermally-conductive,vapor-permeable member. The thermally-conductive, vapor-permeable memberincludes a drape-interface member having a first side and a second,patient-facing side, wherein the first side of the drape-interfacemember is proximate the second, patient facing side of thehigh-moisture-vapor-transmission-rate drape; a patient-interface memberhaving a first side and a second, patient-facing side, wherein thesecond, patient-facing side of the patient-interface member is proximateto the patient; and a coupling member that thermally couples thedrape-interface member and the patient-interface member. The wounddressing further includes a liquid-processing member disposed betweenthe drape-interface member and the patient-interface member, wherein theliquid-processing member is operable to at least temporarily retainliquids from the wound. The thermally-conductive, vapor-permeable memberis operable to conduct body heat from the patient to thehigh-moisture-vapor-transmission-rate drape to enhance transmission ofvapor through the high-moisture-vapor-transmission-rate drape. A numberof additional elements may be added to further enhance transmissionacross the high-moisture-vapor-transmission-rate drape.

According to another illustrative embodiment, a method for treating awound on a patient includes covering the wound with a wound dressing.The wound dressing includes a high-moisture-vapor-transmission-ratedrape having a first side and a second, patient-facing side, athermally-conductive, vapor-permeable member, and a liquid-processingmember. The method also includes using the thermally-conductive,vapor-permeable member to conduct heat from the patient's body to thehigh-moisture-vapor-transmission-rate drape to enhance vaportransmission.

According to another illustrative embodiment, a method of manufacturinga wound dressing includes providing a thermally-conductive,vapor-permeable member. The thermally-conductive, vapor-permeable memberincludes a drape-interface member having a first side and a second,patient-facing side; a patient-interface member having a first side anda second, patient-facing side, wherein the second, patient-facing sideof the patient-interface member is for placing proximate to the patient;and a coupling member thermally coupling the drape-interface member andthe patient-interface member. The method also includes disposing aliquid-processing member between the drape-interface member and thepatient-interface member, wherein the liquid-processing member isoperable to at least temporarily retain liquids from the wound; anddisposing a high-moisture-vapor-transmission-rate drape having a firstside and a second, patient-facing side over the thermally-conductive,vapor-permeable member, wherein the first side of the drape-interfacemember is proximate the second, patient-facing side of thehigh-moisture-vapor-transmission-rate drape.

Other aspects, features, and advantages of the illustrative embodimentswill become apparent with reference to the drawings and detaileddescription that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of an illustrative embodiment of a wounddressing on a patient's wound;

FIG. 2 is an exploded, perspective view, with a portion (an edge) shownin cross section, of an illustrative embodiment of a wound dressing;

FIG. 3 is a perspective view, with a portion shown in cross section, ofthe wound dressing of FIG. 2 shown with a plurality nano-antennas;

FIG. 4 is a perspective view, with a portion shown in cross section, ofa portion of the wound dressing of FIG. 3;

FIG. 5 is a cross section of an illustrative embodiment of a portion ofa wound dressing including a filtering layer;

FIG. 6 is a cross section of an illustrative embodiment of a portion ofa wound dressing including a hydro-activated, exothermic material;

FIG. 7 is a cross section of an illustrative embodiment of a portion ofa wound dressing including an electrical heating element;

FIG. 8 is a cross section of an illustrative embodiment of a portion ofa wound dressing;

FIG. 9 is a cross section of an illustrative embodiment of a portion ofa wound dressing including inductive elements;

FIG. 10 is a cross section of an illustrative embodiment of a wounddressing shown on a patient;

FIG. 11 is a plan view of the illustrative embodiment of a wounddressing of FIG. 10;

FIG. 12 is a cross section of an illustrative system for treating awound;

FIG. 13 is a cross section of an illustrative system for treating awound; and

FIG. 14 is a cross section of an illustrative embodiment of a portion ofa wound dressing.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of illustrative, non-limitingembodiments, reference is made to the accompanying drawings that form apart hereof These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it isunderstood that other embodiments may be utilized and that logicalstructural, mechanical, electrical, and chemical changes may be madewithout departing from the spirit or scope of the invention. To avoiddetail not necessary to enable those skilled in the art to practice theembodiments described herein, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is not to be taken in a limiting sense, and the scope of theillustrative embodiments are defined only by the appended claims.

The illustrative medical systems, dressings, and methods herein improvethe fluid management of a wound. The illustrative medical systems,dressings, and methods thermally-enhance transmission of vapor across asealing member to allow the system or dressing to process more liquidthan otherwise possible.

Referring now primarily to FIGS. 1-4, an illustrative embodiment of awound dressing 102 is presented. In FIG. 1, the wound dressing 102 isshown on a wound 104, or tissue site The wound is through a patient's106 epidermis 108, a dermis 109, and into subcutaneous tissue 110. Thewound dressing 102 includes a thermally-conductive, vapor-permeablemember 112 and a liquid-processing member 114. While referencing only“vapor” in its name, the thermally-conductive, vapor-permeable member112 is operable to allow vapor and liquid to pass. Thethermally-conductive, vapor-permeable member 112 and liquid-processingmember 114 are covered by a high-moisture-vapor-transmission-rate drape116 (high-MVTR drape). The thermally-conductive, vapor-permeable member112 is operable to conduct body heat from the patient 106 at or near thewound 104 to the high-moisture-vapor-transmission-rate drape 116 toenhance transmission of vapor through thehigh-moisture-vapor-transmission-rate drape 116.

The heat captured by the thermally-conductive, vapor-permeable member112 of the wound dressing 102 and delivered specifically to thehigh-moisture-vapor-transmission-rate drape 116 increases vaportransmission through the high-moisture-vapor-transmission-rate drape116. As described further below, in addition to or separate fromcapturing body heat, other sources of internal and external heat may beutilized with the wound dressing 102 to increase vapor transmissionthrough the high-moisture-vapor-transmission-rate drape 116.

Enhancing the vapor transmission through the wound dressing 102maximizes the capacity of the wound dressing 102. The wound dressing 102becomes operable to process more liquid over time than the wounddressing 102 can hold at one time The wound dressing 102 effectuallyremoves or manages liquid from the wound 104. The increased vaportransmission can be notable. For example, increasing the temperaturefrom 20° C. to 30° C. or 40° C. may add orders of magnitude to theevaporation rate. In one illustrative, non-limiting example, a 1.3 foldincrease in evaporation rate per degree was associated with each degreeincrease in Celsius (C) from 25° C. to 37° C. The increased evaporationrate in turn may greatly enhance the amount of liquid from the wound 104that may be processed over time by the wound dressing 102.

The high-moisture-vapor-transmission-rate drape 116 has a first side 118and a second, patient-facing side 120. “Moisture Vapor TransmissionRate” or “MVTR” represents the amount of moisture that can pass througha material in a given period of time Thehigh-moisture-vapor-transmission-rate drape 116 will typically have anMVTR greater than 300 g/24 hours/m² and more typically a value greaterthan or equal to 1000 g/24 hours/m². Thehigh-moisture-vapor-transmission-rate drape 116 allows vapor to egressfrom the wound through the wound dressing 102 to the atmosphere. Thehigh-moisture-vapor-transmission-rate drape 116 may comprise any ofnumerous materials, such as any of the following: hydrophilicpolyurethane, cellulosics, hydrophilic polyamides, polyvinyl alcohol,polyvinyl pyrrolidone, hydrophilic acrylics, hydrophilic siliconeelastomers, and copolymers of these. As one specific, illustrative,non-limiting embodiment, the high-moisture-vapor-transmission-rate drape116 may be formed from a breathable cast matt polyurethane film soldunder the name INSPIRE 2301 from Expopack Advanced Coatings of Wrexham,United Kingdom. That illustrative film has a MVTR (inverted cuptechnique) of 14400 g/m²/24 hours. Thehigh-moisture-vapor-transmission-rate drape 116 may have variousthicknesses, such as 10 to 40 microns (μm), e.g., 15, 20, 25, 30, 35, 40microns or any number in the stated range.

A peripheral edge 122 of the high-moisture-vapor-transmission-rate drape116 has an attachment device 124 on the second, patient-facing side 120.The attachment device 124 secures or helps secure thehigh-moisture-vapor-transmission-rate drape 116 to the patient's intactskin at or near the wound 104. The attachment device 124 may be amedically-acceptable, pressure-sensitive adhesive; a double-sided drapetape; paste; hydrocolloid; hydro gel; or other sealing devices orelements.

The thermally-conductive, vapor-permeable member 112functionally'conducts heat from the patient 106 at or near the wound 104to the high-moisture-vapor-transmission-rate drape 116 and allows orenhances vapor transmission through the thermally-conductive,vapor-permeable member 112. While the thermally-conductive,vapor-permeable member 112 may be formed as integral components, thethermally-conductive, vapor-permeable member 112 may nonetheless beviewed as comprising three portions or members a drape-interface member126, a patient-interface member 128, and a coupling member 130. Thedrape-interface member 126 has a first side 132 and a second,patient-facing side 134. The first side 132 of the drape-interfacemember 126 is proximate the second, patient-facing side 120 of thehigh-moisture-vapor-transmission-rate drape 116. The patient-interfacemember 128 has a first side 136 and a second, patient-facing side 138.The second, patient-facing side 138 of the patient-interface member 128is proximate to the patient 106. The coupling member 130 thermallycouples the drape-interface member 126 and the patient-interface member128.

The thermally-conductive, vapor-permeable member 112 may be formed fromany material that conducts thermal energy and allows liquid and vapor totransgress the material. For example, the thermally-conductive,vapor-permeable member 112 may comprise one or more of the following:woven or non-woven material, activated carbon material, porous foam,sintered polymer, carbon fiber material, woven metallic fibers, zincoxide, or mesh fabric. The thermally-conductive, vapor-permeable member112 is sized and configured to be flexible enough to conform to theshape of the wound 104.

Disposed between the drape-interface member 126 and thepatient-interface member 128 is the liquid-processing member 114. Theliquid-processing member 114 is operable to at least temporarily retainliquids from the wound 104. The liquid-processing member 114 has a firstside 140 and a second, patient-facing side 142. The first side 140 isproximate the second, patient-facing side 134 of the drape-interfacemember 126. The second, patient-facing side 142 is proximate to thefirst side 136 of the patient-interface member 128.

The liquid-processing member 114 functions to retain, at leasttemporarily, liquids from the wound 104. The liquid-processing member114 buffers liquids while waiting on evaporation or removal or may storea certain quantity of liquids for other reasons. The liquid-processingmember 114 may be formed from one or more of the following: open-cellfoam, non-woven material, a super-absorbent material, gel materials,absorbent clays or inorganic or polymer particulates, and nanoparticles.

In addition to or separate from capturing the patient's body heat andconducting the heat from at or near the wound 104 to thehigh-moisture-vapor-transmission-rate drape 116, thermal energy may beadded to enhance evaporation from an internal heat source or externalheat source. For example, heat from external air temperature, light,artificial radiation (infrared), hydro-activated chemicals, inductivematerials, piezoelectric members, electric heating elements, or sonicheating (thermo-acoustic) may be used to enhance transmission of vaporthrough the high-moisture-vapor-transmission-rate drape 116.

With reference to FIGS. 4-6, a plurality of nano-antennas 144 ornantennas have been added on the first side 118 of thehigh-moisture-vapor-transmission-rate drape 116. The plurality ofnano-antennas 144 are a way of harvesting the environmental energy,e.g., energy from light or heat from the patient. A nano-antenna is anelectromagnetic collector designed to absorb specific wavelengths thatare proportional to the size of the nano-antenna. The nano-atennas 144may be sized to focus on absorbing infrared radiation with wavelengthsfrom 1 micron to 300 microns and may, in some embodiments, focus on 12micron wavelengths which are the wavelength that the human body atnormal temeprature emits as heat. Design of the nano-antenna 144 may bea type of interlocking spiral such as those from MicroContinuum Inc.These type of antennas are manufactured by photo-lithography using goldfoil on a plastic sheet substrate. The energy harnessed is electrical.

Separate or in addition to the nano-antennas 144, thehigh-moisture-vapor-transmission-rate drape 116 may include corrugatedportions 146 as shown in FIG. 6. The corrugated portions 146 increasethe surface area available to assist with evaporation and may encourageturbulent air flow across the first side 118 of thehigh-moisture-vapor-transmission rate drape 116.

Referring primarily to FIGS. 1-4, in operation, according to oneillustrative embodiment, the thermally-conductive, vapor-permeablemember 112, which has the liquid-processing member 114 between portionsthereof, is disposed proximate to the wound 104. The patient-interfacemember 128 of the thermally-conductive, vapor-permeable member 112 isdisposed proximate to the wound 104. Thehigh-moisture-vapor-transmission-rate drape 116 is disposed over thethermally-conductive, vapor-permeable member 112. In particular, thesecond, patient-facing side 120 of thehigh-moisture-vapor-transmission-rate drape 116 is disposed proximate tothe first side 132 of the drape-interface member 126.

Before applying the high-moisture-vapor-transmission-rate drape 116, ifapplicable, release liners (not shown) may be removed from theattachment device 124. The wound dressing 102 may remain on the wound104 for a few hours up to many days, e.g., 2 days, 4 days, 7 days, ormore A saturation indicator (visual indicator of moisture)(not shown)may be added to the thermally-conductive, vapor-permeable member 112 orliquid-processing member 114 to indicate when the wound dressing 102 isfull. If nano-antennas 144 are included (e.g., FIGS. 3-4, 6, 12), thenano-antennas 144 may absorb energy from ambient light or may receivelight from a directed light source (see, e.g., FIG. 12).

The wound 104 produces a liquid, e.g., exudate, that flows through thepatient-interface member 128 and into the liquid-processing member 114,which temporarily holds the liquid. The liquid in the liquid-processingmember 114 that is against or near thehigh-moisture-vapor-transmission-rate drape 116 evaporates and istransmitted through the high-moisture-vapor-transmission-rate drape 116.The transmission rate through the high-moisture-vapor-transmission-ratedrape 116 is increased or enhanced by the thermal energy delivery fromthe patient 106 through the thermally-conductive, vapor-permeable member112. The transmission rate may further be enhanced by additional energyadded externally or internally as presented elsewhere herein.

Referring now primarily to FIG. 5, a cross section of a portion of awound dressing 102 is shown according to one illustrative embodiment.This embodiment is analogous to the embodiment of FIG. 1, except afiltering layer 148 has been added. The filtering layer 148 is showndisposed between the high-moisture-vapor-transmission-rate drape 116 andthe drape-interface member 126 of the thermally-conductive,vapor-permeable member 112. It should be understood that the filteringlayer 148 may be at any location between the patient and thehigh-moisture-vapor-transmission-rate drape 116. It should also beunderstood that filtering layer 148 may be used with any embodimentherein.

The filtering layer 148 may serve one or more purposes. The filteringlayer 148 may prevent any substances other than water vapor fromreaching the high-moisture-vapor-transmission-rate drape 116. Inaddition or separately, the filtering layer 148 may serve to filterodors from the vapor transmitted through thehigh-moisture-vapor-transmission-rate drape 116 to the atmosphere. Thefiltering layer may be formed from activated carbon material, activatedclays (such as Bentonite), silicone resins, or coated porous (foams,sintered media) elements.

Referring primarily to FIG. 6, an illustrative embodiment of a portionof a wound dressing 102 is shown that is analogous to the wound dressing102 of FIG. 1, except that the high-moisture-vapor-transmission-ratedrape 116 includes corrugated portions 146 and nano-antennas 144 and thewound dressing 102 includes a hydro-activated, exothermic material 150.The corrugated portions 146 and nano-antennas 144 have previously beendiscussed. The hydro-activated, exothermic material 150 may be disposedon or in the liquid-processing member 114 near the drape-interfacemember 126. When the hydro-activated, exothermic material 150 is exposedto a watery liquid, a resultant chemical reaction produces heat. As oneillustrative, non-limiting example, the hydro-activated, exothermicmaterial 150 may be calcium oxide such that when water in the exudatereaches the hydro-activated, exothermic material 150 a reaction occurs:CaO(s)+H2O(l)→Ca(OH)2(s). Another example, albeit a highly exothermic(and more caustic) one, is NaO_((s))+H₂O_((l))→NaOH_((s)). Anotherexample (used in hand warmers for example) is4Fe_((s))+3O_(2(g))→2Fe₂O_(3(s)). This reaction is one way, but areversible reaction may be used as well.

Referring now primarily to FIG. 7, an illustrative embodiment of aportion of a wound dressing 102 that includes an internal heat source inthe form of an electrical heating element 152 is presented. The wounddressing 102 is analogous in most respects to the wound dressing of FIG.1, except that it further includes the electrical heating element 152and associated components. The electrical heating element 152 may be aresistive heating element that is disposed inside or on thethermally-conductive, vapor-permeable member 112 and is therebythermally coupled to the high-moisture-vapor-transmission-rate drape116. The electrical heating element 152 provides thermal energy whenenergized.

The illustrative electrical heating element 152 is shown as a pluralityof electrical conduits disposed within the thermally-conductive,vapor-permeable member 112 and electrically coupled to one another byleads 154. The electrical heating element 152 is electrically coupled toa control circuit 156 by another lead 158. A power supply 160 iselectrically coupled to the control circuit 156 by another lead 162. Thecontrol circuit 156 may be used to set the desired temperature and tocontrol the heat developed by the electrical heating element 152.

Referring now primarily to FIG. 8, an illustrative embodiment of aportion of a wound dressing 102 that includes an internal heat source inthe form of a piezoelectric member 164 is shown. The wound dressing 102is analogous in most respects to the wound dressing of FIG. 1, exceptthat the wound dressing 102 further includes the piezoelectric member164. The piezoelectric member 164 is operable to provide energy to thewound dressing 102 when the piezoelectric member 164 is moved. Thepiezoelectric member 164 generates an electrical current during flexingthat is then used to generate heat.

Referring now primarily to FIG. 9, an illustrative embodiment of aportion of a wound dressing 102 that includes inductive elements 166 anda source of magnetic energy 168 is presented. The wound dressing 102 isanalogous in most respects to the wound dressing of FIG. 1, except theinductive elements 166 have been added. The inductive elements 166 aredisposed within or on the thermally-conductive, vapor-permeable member112. The source of magnetic energy 168 emits magnetic energy that isreceived by the inductive elements 166 to produce thermal energy that isconducted to the thermally-conductive, vapor-permeable member 112 andthereby to the high-moisture-vapor-transmission-rate drape 116.

Referring now primarily to FIGS. 10 and 11, an illustrative embodimentof a wound dressing 102 is presented that is analogous in most respectsto the wound dressing 102 of FIG. 1, except that the wound dressing 102includes a patient-interface member 128 that is larger than thedrape-interface member 126 of the thermally-conductive, vapor-permeablemember 112. The patient-interface member 128 is larger to provide agreater surface area over which to capture heat from the patient. A seal170 may be provided on a portion of the patient-interface member 128proximate to an edge of the drape-interface member 126 to provide afluid seal. The seal inhibits fluid flow but allows thermal energy topass. Thus, in this illustrative embodiment, the planar surface area(A₁) of the drape-interface member 126 is less than the planar surfacearea (A₂) of the patient-interface member 128, i.e., A₁<A₂. An adhesive(not shown) may be applied on peripheral portion of the patient-facingside of the patient-interface member 128 to hold the additional portionof the patient-interface member 128 to intact skin on the patient.

Referring to FIGS. 5-11, in operation, according to another illustrativeembodiment, the wound dressing 102 is disposed proximate to the wound104. The patient-interface member 128 is proximate to the wound 104. Theother layers or members are assembled or pre-assembled as shown in thefigures with the high-moisture-vapor-transmission-rate Drape on the top(for the orientation shown).

Referring now primarily to FIG. 5, in operation, the vapor leaving thethermally-conductive, vapor-permeable member 112 moves through thefiltering layer 148, which removes odor or particulates that mightotherwise escape. Referring primarily to FIG. 6, the vapor transmissionrate is enhanced by the patient's body heat and heat from thehydro-activated, exothermic material 150 once the watery liquid reachesthe hydro-activated, exothermic material 150. For embodiments includingthe nano-antennas 144 (e.g., FIG. 3, 4, 6), additional energy is addedthereby. Moreover, for the embodiment shown in FIG. 6, the transmissionrate may be relatively increased by using a greater surface area due tothe corrugated portions 146.

Referring primarily to FIG. 7, in operation according to oneillustrative embodiment, the transmission rate is enhanced by thepatient's body heat and heat from the electrical heating element 152.The amount of heat added by the electrical heating element 152 iscontrolled by the control circuit or controller 156. An electrical fillindicator (not shown) may be included in the liquid-processing member114 and electrically coupled to the control circuit 156 such that thecontrol circuit 156 activates the electrical heating element 152 oncethe liquid-processing member 114 is saturated. Alternatively, thecontrol circuit 156 may activate the electrical heating element 152based on timer intervals or when manually activated.

Referring primarily to FIG. 8, in operation according to oneillustrative embodiment, the transmission rate is enhanced by thepatient's body heat and heat from the piezoelectric member 164. Thepiezoelectric member 164 may take movement and create thermal energy. Inanother illustrative embodiment, the element labeled 164 may be amaterial that otherwise generates heat as the element is flexed. Forexample, without limitation, the following may be used tastablepolyester polyurethane elastomers based on the system polycaprolactonediol (Capa 225)/trans 1.4-cyclohexane diisocyanate (CHDI)/1.4-butanediol (1.4-BD) and 1.4-cyclohexane dimethanol (1.4-CHDM). Referring nowprimarily to FIG. 9, the transmission rate is enhanced by the patient'sbody heat and heat from the inductive elements 166 that are activated bythe source of magnetic energy 168.

Referring now primarily to FIG. 12, an illustrative system 100 fortreating a wound 104 on a patient 106 is presented. The system 100includes a wound dressing 102, which is analogous in many respects tothe wound dressing 102 of FIG. 1. The system 100 provides for enhancedliquid management and also for the application of reduced pressure on awound 104.

The system 100 includes a manifold member 172 disposed proximate to thewound 104. In this illustrative example, the wound 104 extends throughepidermis 108, dermis 109, and into subcutaneous tissue 110. Themanifold member 172 is a substance or structure that is provided toassist in applying reduced pressure to, delivering fluids to, orremoving fluids from a tissue site or wound 104. The manifold member 172includes a plurality of flow channels or pathways that distribute fluidsprovided to and removed from the tissue site around the manifold member172. In one illustrative embodiment, the flow channels or pathways areinterconnected to improve distribution of fluids provided to or removedfrom the wound 104. The manifold member 172 may be a biocompatiblematerial that is capable of being placed in contact with the wound 104and distributing reduced pressure. Examples of manifold members 172include, without limitation, one or more of the following: devices thathave structural elements arranged to form flow channels, such as, forexample, cellular foam, open-cell foam, porous tissue collections,liquids, gels, and foams that include, or cure to include, flowchannels; porous material porous, such as foam, gauze, felted mat, orany other material suited to a particular biological application; orporous foam that includes a plurality of interconnected cells or poresthat act as flow channels, e.g., a polyurethane, open-cell, reticulatedfoam such as GranuFoam material manufactured by Kinetic Concepts,Incorporated of San Antonio, Tex.; a bioresorbable material; or ascaffold material.

In some situations, the manifold member 172 may also be used todistribute fluids such as medications, antibacterials, growth factors,and various solutions to the tissue site Other layers may be included inor on the manifold member 172, such as absorptive materials, wickingmaterials, hydrophobic materials, and hydrophilic materials. In oneillustrative, non-limiting embodiment, the manifold member 172 may beconstructed from a bioresorbable material that remains in a patient'sbody following use of the reduced-pressure dressing. Suitablebioresorbable materials include, without limitation, a polymeric blendof polylactic acid (PLA) and polyglycolic acid (PGA). The polymericblend may also include without limitation polycarbonates, polyfumarates,and capralactones.

The manifold member 172 may further serve as a scaffold for newcell-growth, or a scaffold material may be used in conjunction with themanifold member 172 to promote cell-growth. A scaffold is a substance orstructure used to enhance or promote the growth of cells or formation oftissue, such as a three-dimensional porous structure that provides atemplate for cell growth. Illustrative examples of scaffold materialsinclude calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites,carbonates, or processed allograft materials.

As with other embodiments herein, the wound dressing 102 includes ahigh-moisture-vapor-transmission-rate drape 116; a thermally-conductive,vapor-permeable member 112; and a liquid-processing member 114. Thehigh-moisture-vapor-transmission-rate drape 116 may includenano-antennas 144. Applied on or through thehigh-moisture-vapor-transmission-rate drape 116 is a reduced-pressureinterface 174. In one illustrative embodiment, the reduced-pressureinterface 174 is a T.R.A.C.® Pad or Sensa T.R.A.C.® Pad available fromKCI of San Antonio, Tex.

An external energy source 176 may be used to provide additional energyto the wound dressing 102. For example, the external energy source 176may be a light source 178, e.g., an LED light, that provides light tothe high-moisture-vapor-transmission-rate drape 116 directly or byproviding energy to the nano-antennas 144.

The high-moisture-vapor-transmission-rate drape 116 creates a sealedspace 180 between the wound 104 and the second, patient-facing side 120of the high-moisture-vapor-transmission-rate drape 116. Areduced-pressure source 182 is fluidly coupled to the sealed space 180.The reduced-pressure source 182 may be any device for supplying areduced pressure, such as a vacuum pump, wall suction, micro-pump, orother source. While the amount and nature of reduced pressure applied toa tissue site will typically vary according to the application, thereduced pressure will typically be between −5 mm Hg (−667 Pa) and −500mm Hg (−66.7 kPa) and more typically between −75 mm Hg (−9.9 kPa) and−300 mm Hg (−39.9 kPa).

The reduced-pressure source 182 may be fluidly coupled to the sealedspace 180, which includes the manifold member 172, by a reduced-pressuredelivery conduit 184 and the reduced-pressure interface 174 or bydirectly inserting the reduced-pressure delivery conduit 184 through thehigh-moisture-vapor-transmission-rate drape 116 into the sealed space180. In addition, the fluid coupling may be due to the position of thereduced-pressure source 182; for example, if the reduced-pressure source182 is a micro-pump, the intake may be directly, fluidly coupled to thesealed space 180. In addition, in the latter example, the micro-pump isthermally coupled to the high-moisture-vapor-transmission-rate drape116.

In operation, according to one illustrative embodiment, the manifoldmember 172 is disposed proximate to the wound 104. The wound dressing102 is placed proximate to a first side 173 of the manifold member 172.The high-moisture-vapor-transmission-rate drape 116 over the patient'sskin creates the sealed space 180. Using the reduced-pressure interface174 or otherwise, the reduced-pressure delivery conduit 184 is fluidlycoupled to the sealed space 180 and thereby the manifold member 172.Reduced pressure is then applied to help treat the wound 102. In theembodiment shown, liquids are delivered to the reduced-pressure source182, but evaporation and transmission through thehigh-moisture-vapor-transmission-rate drape 116 may also occur. Forembodiments in which the reduced-pressure source 182 is a micro-pump,the liquid will be retained in the wound dressing 102 until transmittedthrough the high-moisture-vapor-transmission-rate drape 116. Thetransmission rate is enhanced by the patient's body heat (deliveredthrough the thermally-conductive, vapor-permeable member 112) and may beenhanced by nano-antennas 144 if included. The nano-antennas 144 may beenergized by a light source 178.

Referring now primarily to FIG. 13, another illustrative embodiment of awound dressing 102 is presented. The wound dressing 102 is analogous inmost respects to the wound dressing 102 of FIG. 1, except externalbaffles 186 and an air mover 188 have been added. The external baffles186 are on the first side of the high-moisture-vapor-transmission-ratedrape 116 and form a channel 190. The air mover 188 is fluidly coupledto the channel 190 by a conduit 192. The air mover 188 provides air flowagainst the first side 118 of the high-moisture-vapor-transmission-ratedrape 116 and thereby further increases the evaporation rate. Thecomponents of the various figures may be combined with others. Thus, forexample, the air mover 188 and external baffles 186 may be added to anyof the other embodiments herein.

Referring now to FIG. 14, another illustrative embodiment of a portionof a wound dressing 102 is presented. The wound dressing 102 isanalogous in most respects to the wound dressing 102 of FIG. 1. Thewound dressing 102 has a thermally-conductive, vapor-permeable member112. A liquid-processing member 114 is between portions of thethermally-conductive, vapor-permeable member 112. The wound dressing 102further includes a high-moisture-vapor-transmission-rate drape 116. Thethermally-conductive, vapor-permeable member 112 has a drape-interfacemember 126, a patient-interface member 128, and a coupling member 130.In this embodiment, the coupling member 130 is presented in a differentlocation in part to emphasize that the coupling member 130 may be innumerous locations.

In the embodiments presented previously, the coupling member 130 hasbeen to one side of the liquid-processing member 114. In theillustrative embodiment of the present embodiment, the coupling member130 extends from the patient-interface member 128 to the drape-interfacemember 126 through the body or main portion of the liquid-processingmember 114. Because it is generally desirable to transfer heat from thepatient to the drape-interface member 126 without heating up theliquid-processing member 114, insulation 194 may be placed around thecoupling member 130. It should be understood that the coupling member130 functions to thermally couple the drape-interface member 126 and thepatient-interface member 128 and may be located at any point withrespect to those members, e.g., sides or middle or any where between.

Although the present invention and its advantages have been disclosed inthe context of certain illustrative, non-limiting embodiments, it shouldbe understood that various changes, substitutions, permutations, andalterations can be made without departing from the scope of theinvention as defined by the appended claims. It will be appreciated thatany feature that is described in connection to any one embodiment mayalso be applicable to any other embodiment. For example, withoutlimitation, the nano-antennas 144 may be added to any embodiment herein.As another example, without limitation, the filtering layer 148 may beadded to any embodiment herein. As another example, without limitation,the corrugated portions 146 may be added to any of the embodimentsherein.

As another example, without limitation, the hydro-activated, exothermicmaterial 150 may be added to any of the embodiments herein. As stillanother example the electrical heating element 152 (and associatedcomponents) may be added to any embodiment herein or the piezoelectricmember 164 added to any embodiment. As still, another example, withoutlimitation, reduced pressure (see FIG. 12) may be used with any of theembodiments. As one more example, without limitation, the externalbaffles 186 and air mover 188 (FIG. 13) may be used with any embodiment.Moreover, the different components may be used in any combination.

Thus, for example, without limitation, a wound dressing 102 may have anano-antennas 144 on the high-moisture-vapor-transmission-rate drape116, a filtering layer 148 below (for orientation shown in FIG. 5), ahydro-activated, exothermic material 150 proximate the filtering layer148, and an electrical heating element 152 in the thermally-conductive,vapor permeable member 112. Numerous other examples are possible.Finally, while the illustrative embodiments have been shown using bodyheat directed by the thermally-conductive, vapor-permeable member 112,it should be appreciated that some of the embodiments may forgo such acomponent and use other heating elements alone, e.g., thehydro-activated, exothermic material 150; electrical heating element152; or piezoelectric member 164.

According to another illustrative embodiment, the piezoelectric member164 (FIG. 8) may be included with the reduced-pressure components ofFIG. 12. Then in operation, the reduced-pressure components may be usedin a pulsed fashion to move and excite the piezoelectric member 164 togenerate heat.

The illustrative embodiments herein may provide numerous perceivedadvantages for healthcare providers and patients. A number of possibleexamples follow. For example, the wound dressing 102 may have anenhanced capacity because the, wound dressing 102 is able to offloadliquid from the wound dressing 102 in the form of vapor exiting thewound dressing 102 through the high-moisture-vapor-transmission-ratedrape 116. And, because of the additional thermal energy, the wounddressings 102 are operable to transmit relatively more liquid throughthe high-moisture-vapor-transmission-rate drape 116 over a given timeMoreover, the wound dressings 102 may stay in place longer. The wounddressings 102 may be used without requiring additional training. Thewound dressings 102 may convert liquids retained into the wound dressing102 to a gel and thereby make disposal easier.

It will be understood that the benefits and advantages described abovemay relate to one embodiment or may relate to several embodiments. Itwill further be understood that reference to “an” item refers to one ormore of those items.

The steps of the methods described herein may be carried out in anysuitable order, or simultaneously where appropriate.

Where appropriate, aspects of any of the embodiments described above maybe combined with aspects of any of the other embodiments described toform further examples having comparable or different properties andaddressing the same or different problems.

It will be understood that the above description of preferredembodiments is given by way of example only and that variousmodifications may be made by those skilled in the art. The abovespecification, examples and data provide a complete description of thestructure and use of exemplary embodiments of the invention. Althoughvarious embodiments of the invention have been described above with acertain degree of particularity, or with reference to one or moreindividual embodiments, those skilled in the art could make numerousalterations to the disclosed embodiments without departing from thescope of the claims.

1. A wound dressing comprising: a high-moisture-vapor-transmission-ratedrape having a first side and a second, patient-facing side; athermally-conductive, vapor-permeable member comprising: adrape-interface member having a first side and a second, patient-facingside, wherein the first side of the drape-interface member is proximatethe second, patient-facing side of thehigh-moisture-vapor-transmission-rate drape, a patient-interface memberhaving a first side and a second, patient-facing side, wherein thesecond, patient-facing side of the patient-interface member is proximateto the patient, and a coupling member that thermally couples thedrape-interface member and the patient-interface member; aliquid-processing member disposed between the drape-interface member andthe patient-interface member, wherein the liquid-processing member isoperable to at least temporarily retain liquids from the wound; andwherein the thermally-conductive, vapor-permeable member is operable toconduct body heat from the patient to thehigh-moisture-vapor-transmission-rate drape to enhance transmission ofvapor through the high-moisture-vapor-transmission-rate drape.
 2. Thewound dressing of claim 1, wherein thehigh-moisture-vapor-transmission-rate drape is less than or equal to 30microns in thickness.
 3. The wound dressing of claim 1, wherein thethermally-conductive, vapor-permeable member comprises an active carbonmember.
 4. The wound dressing of claim 1, wherein thethermally-conductive, vapor-permeable member comprises a material withmetallic fibers.
 5. The wound dressing of claim 1, wherein thethermally-conductive, vapor-permeable member comprises zinc oxide. 6.The wound dressing of claim 1, wherein the thermally-conductive,vapor-permeable member comprises silver.
 7. The wound dressing of claim1, wherein the liquid-processing member comprises one of the following:a foam member, a non-woven member, a super absorbent material, and a gelmaterial.
 8. The wound dressing of claim 1, further comprising afiltering layer disposed between at least a portion of theliquid-processing member and the thermally-conductive, vapor-permeablemember.
 9. The wound dressing of claim 1, further comprisingnano-antennae coupled to the first side of thehigh-moisture-vapor-transmission-rate drape for receiving externalenergy.
 10. The wound dressing of claim 1, wherein thehigh-moisture-vapor-transmission-rate drape is at least partiallycorrugated.
 11. The wound dressing of claim 1, wherein theliquid-processing member comprises a hydro-activated, exothermicmaterial that reacts with wound exudate to generate heat.
 12. The wounddressing of claim 1, wherein the liquid-processing member comprises acalcium oxide that exothermically reacts with wound exudate to generateheat.
 13. The wound dressing of claim 1, further comprising: anelectrical heating element that is operable to provide thermal energywhen energized, wherein the electrical heating element is thermallycoupled to the high-moisture-vapor-transmission-rate drape; a powersupply electrically coupled to the electrical heating element; and acontrol circuit coupled to the power supply and electrical heatingelement.
 14. The wound dressing of claim 1, further comprising apiezoelectric member that is operable to provide thermal energy whenmoved, wherein the piezoelectric member is thermally coupled to thehigh-moisture-vapor-transmission-rate drape.
 15. The wound dressing ofclaim 1, further comprising: a manifold member disposed proximate to thea-patient-interface member of the thermally-conductive, vapor-permeablemember; and a reduced-pressure source fluidly coupled to the manifoldmember.
 16. The wound dressing of claim 1, further comprising: amanifold member disposed proximate to the a-patient-interface member ofthe thermally-conductive, vapor-permeable member; and a micropumpfluidly coupled to the manifold member and thermally coupled to thehigh-moisture-vapor-transmission-rate drape to deliver heat thereto. 17.The wound dressing of claim 1, wherein a planar surface area of thedrape-interface member is less than a planar surface area of thepatient-interface member.
 18. The wound dressing of claim 1, furthercomprising a motion-activated heating element thermally coupled to thehigh-moisture-vapor-transmission-rate drape.
 19. The wound dressing ofclaim 1, further comprising an external heater for transmitting heat tothe first side of the high-moisture-vapor-transmission-rate drape. 20.The wound dressing of claim 1, further comprising external baffles onthe first side of the high-moisture-vapor-transmission-rate drape and anair mover for delivering an air flow in the baffles.
 21. The wounddressing of claim 1, wherein the wound dressing is operable to processmore liquids over time than the dressing can hold without evaporation.22. A method for treating a wound on a patient, the method comprising:covering the wound with a wound dressing comprising: ahigh-moisture-vapor-transmission-rate drape having a first side and asecond, patient-facing side, a thermally-conductive, vapor-permeablemember, and a liquid-processing member; and conducting heat from thepatient's body to the high-moisture-vapor-transmission-rate drapethrough the thermally-conductive, vapor-permeable member to enhancevapor transmission.
 23. The method of claim 22, further comprisingheating the high-moisture-vapor-transmission-rate drape with an externalheat source.
 24. The method of claim 23, wherein the external heatsource comprises an LED light.
 25. The method of claim 22, wherein thewound dressing further comprises a plurality of nano-antennae on thefirst side of the high-moisture-vapor-transmission-rate drape and themethod further comprises exciting the nano-antennae with infraredradiation.
 26. The method of claim 22, further comprising heating thehigh-moisture-vapor-transmission-rate drape with an internal heatsource.
 27. The method of claim 26, wherein the internal heat sourcecomprises a piezoelectric member.
 28. The method of claim 26, whereinthe internal heat source comprises: an electrical heating element thatis operable to provide thermal energy when energized, wherein theelectrical heating element is thermally coupled to thehigh-moisture-vapor-transmission-rate drape; a power supply electricallycoupled to the electrical heating element; and a control circuit coupledto the power supply and electrical heating element.
 29. The method ofclaim 26, wherein the internal heat source comprises a motion-activatedheating element thermally coupled to thehigh-moisture-vapor-transmission-rate drape and the method furthercomprises moving the motion-activated heating element.
 30. The method ofclaim 26, wherein the internal heat source comprises a hydro-activatedexothermic material.
 31. The method of claim 22, wherein the wounddressing further comprises an inductive member and further comprisingexciting the inductive member using magnetic energy. 32.-39. (canceled)40. The method of claim 22, further comprising capturing external energywith nano-antennae coupled to the first side of thehigh-moisture-vapor-transmission-rate drape.
 41. The method of claim 22,further wherein the high-moisture-vapor-transmission-rate drape is atleast partially corrugated.
 42. (canceled)
 43. The method of claim 22,further comprising: disposing a manifold member proximate to the apatient-interface member of the thermally-conductive, vapor-permeablemember; coupling a micro-pump to thehigh-moisture-vapor-transmission-rate drape and the manifold member, andwherein the micropump is thermally coupled to thehigh-moisture-vapor-transmission-rate drape; and heating thehigh-moisture-vapor-transmission-rate drape with the micropump. 44.(canceled)
 45. The method of claim 22, further comprising moving airacross the high-moisture-vapor-transmission-rate drape.
 46. A method ofmanufacturing a wound dressing, the method comprising: providing athermally-conductive, vapor-permeable member comprising: adrape-interface member having a first side and a second, patient-facingside, a patient-interface member having a first side and a second,patient-facing side, wherein the second, patient-facing side of thepatient-interface member is for placing proximate to a patient, and acoupling member thermally coupling the drape-interface member and thepatient-interface member; disposing a liquid-processing member betweenthe drape-interface member and the patient-interface member, wherein theliquid-processing member is operable to at least temporarily retainliquids from a wound; and disposing ahigh-moisture-vapor-transmission-rate drape having a first side and asecond, patient-facing side over the thermally-conductive,vapor-permeable member, wherein the first side of the drape-interfacemember is proximate the second, patient-facing side of thehigh-moisture-vapor-transmission-rate drape.
 47. The method of claim 46further comprising coupling nano antennae to the first side of thehigh-moisture-vapor-transmission-rate drape.
 48. (canceled)